1. Field
The present disclosure relates to wireless communication and, more particularly, to a method and apparatus for transmitting and receiving a Device-to-Device (D2D) signal.
2. Discussion of the Background
Long Term Evolution (LTE) of 3rd Generation Partnership Project (3GPP) allows supporting a Proximity Service (ProSe) so as to satisfy demands associated with public safety. As a discovery technology and broadcasting communication are added to the ProSe, there is a desire for a technology for providing compatibility in an LTE system.
Device-to-device (D2D) communication relates to a communication method having been available since the era of an analog two-way radio and has been used over the very long history. However, D2D communication in a wireless communication system is distinguished from existing D2D communication.
The D2D communication in the wireless communication system indicates communication that uses a transmission and reception technology, for example, a physical channel, of the wireless communication system in a frequency band of the wireless communication system or a band excluding the frequency band, and in this instance, enables user data to be directly transmitted and received between devices, for example, user equipments (UEs), without using an infrastructure, for example, an evolved-NodeB (eNB). That is, two UEs function as a source and a destination of data, respectively, and perform communication. Such a method enables wireless communication to be available in an area outside a limited wireless communication infrastructure and also decreases network load of the wireless communication system.
The D2D communication may be performed through a communication method of using an unlicensed band of a wireless local area network (WLAN), such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, or Bluetooth. However, the communication method using the unlicensed band may not readily provide a planned and controlled service. In particular, performance may be significantly degraded due to interference. On the other hand, D2D communication operated or provided in a licensed band or an inter-system interference controlled environment may support the relatively high quality of service (QoS), may improve the frequency use efficiency through a frequency reuse, and may also increase a communicable distance.
In the case of D2D communication using the licensed band, that is, D2D communication based on cellular communication, resources for D2D communication may be allocated through an eNB. For example, cellular uplink (UL) channels or UL subframes may be used as resources to be allocated. The D2D communication includes D2D data communication and D2D control signal communication. Unlike cellular communications, the D2D communication may be performed without a control by a network. Thus, a plurality of D2D signals may be overlapped in the same time with respect to a UE, for example, a collision of the plurality of D2D signals may occur. Accordingly, there is a need to prevent and/or resolve such a problem.
Also, a User Equipment (UE) having a single transceiver chain is incapable of executing simultaneous transmissions/receptions through various frequency bands. Accordingly, for effective D2D communication in a licensed band, there is a need of assigning a priority a signal for processing D2D signals when a collision occurs among the D2D signals.